Fixes the problem with read mode and existing sincedb reference

Author: andsel

Diff for: lib/filewatch/read_mode/handlers/read_file.rb

@@ -5,6 +5,10 @@ class ReadFile < Base
     def handle_specifically(watched_file)
       if open_file(watched_file)
         add_or_update_sincedb_collection(watched_file) unless sincedb_collection.member?(watched_file.sincedb_key)
+        if sincedb_collection.member?(watched_file.sincedb_key)
+          previous_pos = sincedb_collection.find(watched_file).position
+          watched_file.file_seek([watched_file.bytes_read, previous_pos].max)
+        end
         loop do
           break if quit?
           loop_control = watched_file.loop_control_adjusted_for_stat_size